evo 8 mostly everything is stock. ideals fine starts up fine try to drive it and it'll drive fine for a minute or two then it starts to rock back and forth not wanting to move. in first gear. idk what the problem is. everything is hooked up ive double checked hoses and electrical connections.

 

also have a fairly new coil on plug set up with new spark plugs gapped to .028

 

what exactly does "rock back and forth" mean.

when your on throttle? off?
moving. stopped?

 

yes while on throttle and moving. it wont do it while stopped. i let the car warm up and idle for 5-8 min. and no issues. i double checked the tps with evoscan and it was normal 13%. is there anything else i should check. i don't have any previous logs to cross compare.

 

Whats the setup?

Could need a tune or have a boost leak.

 

stock except for a coil on plug kit. and the previous owners word of a walbro 255 pump and 650 injectors. and an aftermarket manual boost controller hbc i believe, the smooth turning type. and a tial bov.

 

is it throwing any diagnostic trouble codes?

 

nope no codes. no leaks either i checked the o2 sensors they look fine. i double checked the wiring as well. Could it be a compression issue or a transmission issue?

 

Tial VTA? If it's non recirc with the wrong spring and you are on maf, I bet you it's opening up and causing havoc.

 

Sounds like the tune is a bit off when it's cold.

 

It could be pogo - pilot induced oscillation or in this case, driver induced. The 8 with the standard differential likes to send shocks to the front and rear axles and once it starts bouncing the driver, the driver unintentionally starts working the throttle making it worse. I notice, having been in hiding the last three months, my driving skills have decayed, the car hasn't changed, but I now notice some of this. When the car was new I saw this a lot. Then my driving skills improved and it was gone.

This is a car that likes a heavy foot. I don't necessarily mean full throttle but the car doesn't like to be slow.

 

Yeah, but he said it doesn't do it once it's warmed up. Especially with speed density if it doesn't have enough cold enrichment, these cars can run kinda meh until coolant temp is over 160*.

 

So, I fixed the issue. I took apart the throttle body to see if there was any leak/shutting all the way or a build up of gunk, there was. cleaned it all out. I also checked the IACV (idle air control valve) and replaced the rubber gasket. it seemed to have fixed my problem. I also double checked the throttle position sensor with evoscan just to make 100% sure that it was still in the 13-15 percent range. i also double checked my vacuum lines and intake piping all good there. started it. idled great just like before. took it for a drive around a close by parking lot. no issues. no jerking back and forth. I believe the issue was a leaking IACV gasket. I don't know if its ever been replaced. and i don't want to if i don't have to.

thank you all for the suggestions and taking the time to help.